style: linting markdown files

Linting markdown files according to default remark-lint configuration.

Files inside the `public` directory were not linted.

Signed-off-by: oupala <oupala@users.noreply.github.com>

docs/dev/getting-started.md

@@ -1,5 +1,4 @@
-Developer Notes
-===
+# Developer Notes
 
 ## Preparing for running the code
 
@@ -7,20 +6,20 @@ Developer Notes
 
 1. Clone the repository with `git clone https://github.com/codimd/server.git codimd-server`
    (cloning is the preferred way, but you can also download and unzip a release)
+
 2. Enter the directory and run `bin/setup`, which will install npm dependencies
    and create configs. The setup script is written in Bash, you would need bash
    as a prerequisite.
+
 3. Setup the [config file](../configuration-config-file.md) or set up
    [environment variables](../configuration-env-vars.md).
 
-
 ## Running the Code
 
 Now that everything is in place, we can start CodiMD:
 
-4. `yarn run build` will build the frontend bundle. It uses webpack to do that.
-5. Run the server with `node app.js`
-
+1. `yarn run build` will build the frontend bundle. It uses webpack to do that.
+2. Run the server with `node app.js`
 
 ## Running the Code with Auto-Reload
 
@@ -32,11 +31,11 @@ rebuild the frontend or restart the server if necessary.
 The commands will stay active in your terminal, so you will need multiple tabs
 to run both at the same time.
 
-4. Use `yarn run dev` if you want webpack to continuously rebuild the frontend
+1. Use `yarn run dev` if you want webpack to continuously rebuild the frontend
    code.
-5. To auto-reload the server, the easiest method is to install [nodemon](https://www.npmjs.com/package/nodemon)
-   and run `nodemon --watch app.js --watch lib --watch locales app.js`.
 
+2. To auto-reload the server, the easiest method is to install [nodemon](https://www.npmjs.com/package/nodemon)
+   and run `nodemon --watch app.js --watch lib --watch locales app.js`.
 
 ## Structure